Giles 200: Titan IO-375 Engine Scanning

Hey what happened to that Giles 200 project? Well once I figured out that I was getting a laser scanner, I put scanning the engine on hold, because making air cooled engine models with a mechanical arm is well, pretty awful. So, now that I have the laser scanner, it’s full speed ahead! I’m going to be making cooling plenums that will very nicely interface with my cowl openings, and this is one of the places where having a laser scanner is just invaluable.

The first step is to target up the engine. We decided to remove the intake and exhaust for now. Those will get scanned later – the trick we’ll be using to scan them is just sooooo cool, but you’ll have to wait a few days to see that. We hung the engine on a hoist, and again this is one of those things that I just love about this unit – With a mechanical arm, or even a laser scanner that has a fixed head unit, the engine would have to be totally stationary. With the EXAscan, we can just hang the engine on the hoist and spin it around at will. This makes scanning so much easier. Here’s a few pictures of me scanning yesterday:

Air cooled engines are definitely a challenge to scan. Since the fins are often quite thin – especially those at the base of the cylinders – the resolution must be quite fine in order to pick up that level of detail. This means the size of the file grows much larger, and applying the filters to the data takes longer. So, it’s a bit of a delicate balance between getting enough data to see the fins, but not so much that the file becomes unwieldy. There are a few different methods for dealing with projects just like this, and I’m experimenting to find the right solution. I’m pretty sure if I can scan this, I can scan anything. Here’s a screenshot of the scan – the level of detail possible is just amazing to me:

I’m hoping to get this done in the next week, so we can get the motor back up to Sonora and back on the plane, and then get some molds cutting!

One technique to consider is to scan the position model – just scan all of the targets.
Then save the position model out to a text file.
When you need to scan the areas where you need to increase the global resolutions, like the thin fins, simply load the position model and scan the fins at higher resolution (a rule of thumb for the resolution is to set it to 1/4 the size of the fin width). The same is true with ribs on plastic parts.

For Example: If your fin is 1/8″ wide then scan at 1/64″ resolution. You can also scan at about 1/32″ res and then increase the res to 1/64″ after you finish and you will see the fine details appear.

After you have captured the area of interest clean up any excess data andsave it off as its own session. Then start a new session and reload the position model from the text file. Start scanning at a lower resolution for the other areas. Since you are working from the same position model when you bring these two STL files together they will overlay nicely, one high resolution the other low resolution.

Your VxElement software will also allow you to highlight regions and increase the resolution locally, but I have found that for thin features this is not the best method, but rather to scan according to my example above. Increasing local resolution works best for things like embossed lettering, texture, cracks, etc.